To me, the difference is; there are very many people doing wetplate, more each week. There are active forums, suppliers and vendors for the tanks, plateholders, etc. There are workshops put on in several parts of the country, from Will Dunniway on the left coast, to the Ostermans and John Coffer on the right. If you search wetplaters on Flickr, you will discover many groups, where many different photographers post their wetplates each week.
From dryplate we get.....silence. Or maybe I'm not plugged in, but I just don't see anyone doing dryplate. I'd venture to say there are more Daguerreotypists in the country than dryplaters. Correct me if I'm wrong, again, I'm quite involved with wetplate (oh yeah, World Wetplate Day is coming up in a couple months - 3rd year, see website and books of plates taken)
Why? I don't know.